1. Field of the Invention
The present invention relates to bar code scanners and, more particularly, to an improved ergonomic bar code scanning system having a compact housing for either fixed or hand-held disposition at a counter.
2. Description of the Background
Many commercial scanning systems are available for scanning bar codes, e.g., the UPC or EAN bar codes, which are imprinted on products or packaging.
One type of scanning system is generally referred to an omnidirectional scanner. Often these devices can be found mounted in a checkout counter of a supermarket or other retail point-of-sale environment. These scanning systems include a scanning window or aperture at the front of the scanner housing through which a scanning pattern is projected. The scanning pattern is created by a light source, typically a laser, and associated optical components that may produce a pattern of multi-directional scan lines. When an item bearing a bar code is brought into the field of the scan pattern so that at least one of the scan lines completely traverses the bar code, light is reflected off of the bar code and is received back through the window. The reflected light is detected by a photodetector or other light detection means. The signal from the photodetector is then processed by conventional means and forwarded to a microprocessor or other device which decodes the bar-coded information.
In-counter and presentation type scanners use a variety of optical configurations including mirrors, prisms and the like to fold the laser beam and create complex omnidirectional scanning patterns in order to insure that the bar code is scanned completely by at least one scan line so that it can be read accurately irrespective of its orientation within the scan pattern. Examples of such omnidirectional scanning patterns include: comb patterns, orthogonal patterns, interlaced patterns, star-like patterns, lissajous patterns and the like. While such prior art scanners may be suitable for their purpose, their physical configuration of the optical components necessary to produce such complex omnidirectional scanning patterns has resulted in scanner housings which are quite large in size and necessarily fixed.
Additionally the scanning window or aperture generally faces in a single direction. To change the direction of the scanning window and thus the direction of the scanning pattern, it was necessary to move the entire housing. In many applications, this is inconvenient, especially where there is limited counter space.
There have been various approaches to the problem. For example, U.S. Pat. No. 4,713,532 discloses a counter or slot scanner producing an aggressive scanning pattern having three rastered groups of intersecting scans that form a large xe2x80x9csweetspotxe2x80x9d to enable the bar code to be read omnidirectionally. The ""532 scanner has a compact housing with a relatively small xe2x80x9cfootprintxe2x80x9d which can be mounted on or in a counter. Depending upon the orientation of the scan, its window may be horizontal, vertical, or at some other orientation. Devices embodying the teachings of that patent have been sold by the assignee of that patent (and of this application), Metrologic Instruments, Inc., under the designation MS260. However, once the scanner housing was positioned at a particular orientation, it was fixed and could not be easily moved.
In U.S. Pat. No. 5,216,231, to Knowles et al., an omnidirectional presentation scanner is disclosed. This scanner was designed to be mounted above the counter on an adjustable base. The base is constructed to allow the scanner housing to be adjusted in multiple directions so that the scanning pattern is projected in and desired orientation with respect to the counter. However, the base must be permanently secured to the countertop, which prevents the scanner from being lifted by hand to scan large or bulky items which do not fit on the countertop.
U.S. Pat. No. 5,767,501 to Schmidt et al. discloses a hand-held automatic portable bar code symbol scanner with an omnidirectional laser scanning platform mounted in the head of a hand-supportable housing. The hand-supportable housing can also be supported in separate base unit for hands-free omnidirectional presentation type scanning. The base unit is designed to be attached to a counter and is equipped with a pivoting receptacle, which allows the scanning window and therefore the projected scanning pattern to be adjustable about a horizontal axis. While this unit adds great flexibility and makes efficient use of counter space, it requires the user to return the hand-supportable housing to the base unit after each scan requiring alignment of the handle and handle receiving portions. Additionally, while the hand-supportable housing itself is compact, the combination of the hand-supportable housing with the base unit can be bulky and cumbersome in the valuable counterspace of the typical point-of-sale environment.
U.S. Pat. No. 5,479,002 to Heiman et al. discloses another partial solution in the form of a scan head that is adjustably mounted in a ball-and-socket joint on a scan module or housing. The scan head is movable about three mutually orthogonal axes, thereby allowing the operator to steer the light beam emitted from the head. However, the ""002 patent does not disclose or suggest how the scan head and lower housing can be combined in a package that is conveniently hand-held as well as free-standing. Moreover, the design of the ""002 housing as disclosed provides only for a single-line scan pattern and would not easily lend itself to the production of an omnidirectional scanning pattern.
Other attempts to produce compact omnidirectional scanners having adjustable housings or bases include the Symbol Technologies, Inc. Model LS 9100 and the PSC Model Duet omnidirectional scanners. Both units require removal of the hand-held scanner housing from the associated stand for hand-supported scanning.
Consequently, a need remains for a compact scanner configuration incorporating an integral base with an omnidirectional scanning head that is easily adjustable about at least one axis with respect to the base. The scanner being capable of aggressive omnidirectional scanning from both a hands-free standing position on a countertop or hand-supported by a user for scanning lager, bulky items with out requiring the user to remove and/or replace the scanner in its stand.
It is, therefore, an object of the present invention to provide an omnidirectional scanner of compact size, configured with an integrated base and scanning head, wherein the scanning head is easily adjustable with respect to the base, the entire unit being capable of economical manufacture.
It is another object to provide a scanner as described above in which the scanner head is rotationally attached to the base by a dual track sliding support mechanism that results in an rugged and durable integral scanning unit, whereby the head unit pivots easily with little or no friction against the base unit.
It is still another object to provide a bar code scanning system having an improved ergonomic compact housing for hand-held use in which the scanner housing has contoured lateral recesses on opposing sides to fit the hand of the user by providing thumb and finger grips.
It is another object to provide for a scanner having an improved design in which the scanner base provides a secure foundation for the pivoting the scanning head, and yet very little counter space is needed.
It is still another object to incorporate an aggressive and reliable omnidirectional scan platform in a housing as described above, the resulting system being capable of an aggressive omnidirectional scan from a free-standing fixed position on a countertop or while handheld by a user.
According to the present invention, the above-described and other objects are accomplished by providing a compact scanner including an improved ergonomic scanner housing. The scanner housing is formed of two parts, a base unit and a scanning head. The base unit has an upwardly directed curved opening and a pair of opposing arcuate guide rails attached to the inner wall of the base unit below the opening. Mounted to the base unit is the scanning head housing an omnidirectional scanning platform. The scanning head has an exterior curvature conforming to the curved opening of the base unit for rotational seating thereon. A neck portion protrudes from the bottom of the scanning head. The neck portion extends into the opening in the base unit for sliding engagement with the opposing guide rails. In this manner, the scanning head is supported within the opening of said base unit by the guide rails. The guide rails also permit the scanning head to pivot about a horizontal axis while supporting the head to minimize friction.
An omnidirectional scanning platform is housed in the scanning head. The scanning platform includes a light source for generating a light beam, a scanning mechanism and associated optics for producing an omnidirectional scanning for projection through a scanning window for scanning a bar code on abject presented to the scanning pattern, a light collector for a collecting light returned from the bar code, a photodiode for receiving light reflected from said bar code, an A/D conversion circuit for processing the signal produced by the photodiode, a microprocessor for decoding bar-coded information from the reflected light, and a control system for controlling the function of the above components.
The resulting scanning system permits an aggressive omnidirectional scan from a freestanding fixed position atop a counter or while handheld by a user.